Grandmaster Koneru Humpy misplayed a fine position and went down to defending champion Yifan Hou of China in the third game of the Women's World Championship.
Looking good after the first two of the 10-game match, Humpy went for an erroneous plan and Yifan cashed in to go one up. The scoreline now reads 2-1 in the favour of the Chinese 17-year old.
With seven games still to come, Humpy will now be under pressure especially as her loss came with white pieces. The Indian will have to device new ways to tackle Yifan as the wild complications did not work in the third game.
The Queen pawn opening by Humpy did not see another Catalan and Yifan went for a complicated variation right from the beginning.
Typical of the system, Yifan had weaknesses on the king side and her king itself looked a bit vulnerable as the game progressed.
In the middle game, Humpy went for a pawn sacrifice on the queen side to pursue her attack on the other flank but Yifan, who calculates deep, had judged well that the attack was only optical.
By the 25th move, it was clear that white should have looked towards equalise but a mistake here turned the tide decisively in the favour of the Chinese.
Humpy recovered the lost pawn at a huge concession of giving black a central passed pawn and it was all over in quick time thereafter. Yifan won in 37 moves.
"I took my time to think about taking the pawn on 'a2'. My king could get in trouble, but I decided to go for this principal continuation," said Yifan.
"I had a good position, but I was not making good moves," Humpy said on her play in the middle game.
The fourth game of the euro 2,00,000 Championship will be played before the second rest day. Humpy will now have to play two black games in a row.